Impulse turbine propulsion device for marine craft

ABSTRACT

AN IMPULSE PROPULSION WHEEL FOR BOATS AND THE LIKE HAVING A PLURALITY OF BLADES SPACED AROUND THE CIRCUMFERENCE OF A WHEEL AND HAVING OPEN SPACES BETWEEN THEM. THE BLADES BEING SHAPED TO HAVE AT LEAST TWO DISTINCT RADII OF CURVATURE ON HE FACE OF THE BLADE AND BEING MOUNTED TO HAVE THE GREATEST CURVATURE NEAREST THE CENTER OF THE WHEEL AND TO HAVE THE TIP OF THE BLADE ENTER THE WATER AT SUBSTANTIALLY RIGHT ANGLES TO THE SURFACE OF THE WATER AT THE DESIGN SPEED.

June 13, 1972 W.BEARDSLEY 3,669,565

IMPULSE TURBINE PROPULSION DEVICE FOR MARINE CRAFT Filed Sept. 25, 1970I. I ll F/G. r

WATERSURFACE Q INVENTOR. MEL V/LLE w. BEARDSLEY FIG. 2.

ATTORNEY United States Patent IMPULSE TURBINE PROPULSION DEVICE FORMARINE CRAFT Melville W. Beardsley, 40 Windward Drive, Severna Park, Md.21146 Filed Sept. 25, 1970, Ser. No. 75,420

Int. Cl. F04d 17/04 US. Cl. 416--185 5 Claims ABSTRACT OF THE DISCLOSUREAn impulse propulsion wheel for boats and the like having a plurality ofblades spaced around thecircumference of a wheel and having open spacesbetween them..

The blades being shaped to have at least two distinct radii of curvatureon the face of theblade and being mounted to have the greatest curvaturenearest the center of the wheel and to have the tip of the blade enterthe water at substantially right angles to the surface of the water atthe design speed.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION OBJECTS OF THE INVENTION It is an object ofthis invention to provide efiicient shallow water propulsion.

Another object is to improve the efficiency of a propulsion wheel bylimiting the spill of the water toward the axis of the wheel.

Another object is to prevent the entrapment of air by the blade as itenters the water.

Another object-is to provide continuous acceleration of the water towardthe rear as the blades enter the Water.

Another object of the invention is to provide for the release of thewater from the blade as the blades move out of the water.

Still another objective of the present invention is to minimize theenergy loss due to the impact of the blades entering the water.

Other objects, advantages and novel features of the invention willbecome apparent from the. following detailed description of theinvention when considered in conjunction with the accompanying drawingswherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic showing ofthe wheel of this invention with the near end of the wheel removed andthe structure of the interior shown in part.

FIG. 2 is a diagram showing the profile shape of the blade-of apreferred embodiment of the invention.

FIG. 3 illustrates a modification of the blades of FIG. 2 in which theblade is vented by being made in two parts.

FIG. 3a is a vector diagram of the velocities associated withlhe blade,e.g. the bladeof FIG, 3.-

ice

FIG. 4 illustrates a second modification of the blade of FIG. 2 in whichthere are provided steps in the blade and holes for venting the blade.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingwherein like numerals refer to the same or corresponding parts in theseveral views wherein are shown preferred embodiments of the invention,there is shown in FIG. 1 a plurality of blades 11 mounted around theperiphery of the wheel 10 by any suitable means, such as welding,riveting, etc. The wheel 10 is mounted for rotation on a suitablevehicle, boat, Captured Aire Bubble Vehicle, etc. (not shown) and isdriven by a suitable power system (not shown) in the direction shown bythe arrow 12 in FIG. 1. These blades 11 are mounted with open spacesbetween them and with the inner edge 13, the edge nearest the axis ofthe wheel, substantially perpendicular to a radius of the wheel whichpasses through the blade as shown by line 20 in-EIG. 2. The tip edge 14or edge of the blade farther from the axis of the wheel 10 is positionedsuch that at the point of entry into the surface of the water, when thewater is in a 'quiet state, the blade enters substantially at rightangles to the surface of the Water. The wheel is so mounted in thevehicle, that for quiet Water conditions inner edge 13 does not enterbelow the Water level, or is not submerged as the wheel 10 rotates.

As seen in FIG. 2 the blade 11 is constructed with at least twodifferent radii of curvature. These radii are selected to provide acontinuous acceleration of the Water rearward as the wheel rotates andthe blades move deeper into the water. After the blades begin to moveout of the water the rearward component of the velocity reduces butcontinues to impart some force to the entrained Water until the waterspills out of the blades. The mounting of the blades with the inner edgeperpendicular to the radii of the wheel and with some short extensionbeyond the radius to which it is perpendicular is to prevent the waterfrom escaping from the blade into the interior of the wheel. While thespaces between the blades allow the air displaced by the water toescape.

The tip edge 14 of the blade 11 is sharpened to minimize the loss ofefficiency associated with the impact of the blade as it enters thewater surface.

The vector diagrams shown in respect to several of the blades as seen inFIG. 1, indicate the instantaneous relative direction and magnitude ofthe vertical and hori zontal components of velocity as the wheelrotates, but does not reflect the elfect of the horizontal movement ofthe wheel axis as the vehicle moves. In practice, to achieve the desiredangle of entry of the blades into the water the design speed of thevehicle must be considered. In which case the angle of entry may not beexactly perpendicular to the surface of the water, the de sign beingoptimized for the design speed.

The shape of the blade may be described as having a profile such thatthe plane in which the blade face at the tip lies will be in advance ofthe axis of rotation of the wheel and as said plane is moved over thesurface of the blade toward the axis of rotation of the wheel the planeis rotated in the opposite direction to the rotation of the wheel untilat the point of closest proximity to the axis of rotation of the wheelthe plane will be perpendicular to the radius of the wheel at thatpoint.

Referring to FIG. 2 there is illustrated a method of designing the bladestructure wherein the line 20 represents a radius of the wheel and thetwo radii of curvature of the concave surface are shown as being relatedasIWQtdQne, thatis, the long radius of curvature is course, otherrelationships may be selected and more than two radii may be used, evena continuously varying radius curvature may be ideally used. j

The modification of FIG. 3 shows the blade as having a venting slot 21to aid in the escape of the air displaced by the water as the wheelturns and to facilitate the release of the water carried by the blade byallowing air to enter through the slot asthe water spills out of theblade. The small vector diagram of FIG. 3a wherein vector 22 representsthe velocity of the blade; vector 23 represent the desired velocity ofthe water and. vector 24 is the resultant of vectors 22 and 23 andrepresents the desired velocity of the water relative to. the blade.

In FIG. -4 the improved efficiency is accomplished by creating withinthe concave curvature of the blade a series of steps 26 which may bevented by opening 27 through ally mounted equally spaced blades on saidwheel; w

each of said blades having a face, concave 'in the direction of rotationof said wheel, the'curvature of said concave face increasing theacceleration of the wfiuideas. said bladesprogressively-.ententhewsurface of said fluid; and said curvature ofsaid concave face is varied to include at least two different radii ofcurvature so that the tip edge of the blade hasa radius of curvaturegreater than'the inner 'edge'of the blade. 2. A dev ige as claimed in'claim I in which a portion of the blade is stepped on the concav'e facef3. A device as claimed in claimll' invvhich said blades are ventilatedby openingsilocat ed "are'r to the inner edgethan to the ti'p'of theblades.

4. A device as claimed in claim 3 in which a portion of the blade isstepped onthconcave' face.

5. A device asjclaimed'jn claim 3 wherein .said ventilated openingcomprises a slot.

UmTEDs ATEsBATEliTs- 1l',77i),328 7/1930 Titterington 1,441,955 6/1923wa lke nt 416- FOREIGNPAT MSQ". 710,391 6/1954 England 416-486 AR BSC WABQ P ima Er g g sr c. F. SCHI-MIKOWSKIQAssistant. Enaminer i s c 1."

